1. Field of the Invention
The present invention relates to a switched reluctance motor, and more particularly, to a switched reluctance motor capable of simplifying a structure, remarkably reducing the number of assembling processes and protecting a winding coil.
2. Description of the Background Art
A motor is a device for converting an electric energy to a kinetic energy, and such a motor is used as a power source of almost every machine.
In these days, a reluctance motor is used as a power source of household appliances such as a cleaner or the like. The reluctance motor is classified into a synchronous reluctance motor and a switched reluctance motor. The synchronous reluctance motor is driven by sine waves, and the switched reluctance motor is driven by a pulse signal.
FIG. 1 is a perspective view showing one example of a conventional switched reluctance motor, and FIG. 2 is a plan view of a stator of the switched reluctance motor.
As shown, the switched reluctance motor includes: a stator 100 provided with a plurality of salient poles (P) on an inner circumferential surface of a cylindrical body 110, wherein a coil is wound on the salient pole (P); and a rotor 200 provided with protruding pole portions 220 on an outer circumferential surface of a cylindrical lamination body 210, wherein the number of protruding pole portions is the same as that of the salient poles (P). A rotary shaft 300 is pressingly fixed and coupled to the inside of the rotor 200.
As for the salient pole (P) of the stator, insulation materials 130 each having a predetermined area are respectively coupled to both sides of a tooth 120 having a predetermined shape, and a winding coil 140 wound around the tooth 120 is positioned between the insulation materials 130. The salient poles (P) are insertedly fixed to coupling grooves 111 formed at an inner circumferential surface of the cylindrical body 110 of the stator at regular intervals in a circumferential direction, respectively. By inner sides of the plurality of salient poles (P) mounted at the inner circumferential surface of the cylindrical body 110, a receiving space where the rotor 200 is rotatably inserted is formed.
The rotor 200 is formed as a lamination body made in such a manner that a plurality of thin plates are stacked one on top of another, and protruding pole portions 220 are formed at an outer circumferential surface of the lamination body 210 in a longitudinal direction of the lamination body 210, having predetermined widths and heights.
And, a disc-shaped phase indication magnet 230 with a certain thickness is fixedly coupled to the rotary shaft 300. Poles are magnetized at the phase indication magnet 230 in a circumferential direction, and the number of poles corresponds to the number of salient poles (P) of the rotor. A hall sensor 150 for sensing a phase of the phase indication magnet 230 is provided at the stator side 100. And a parking magnet 160 is provided at the stator side 100, wherein the parking magnet 160 holds a position of the rotor 200 when the rotor 200 stops operating, so that the rotor 200 can be positioned at an effective torque generation area of the stator 100 when being initially activated.
The hall sensor 150, a sensor substrate 170 of the hall sensor and the parking magnet 160 are mounted at a holder 400 injection molded into a predetermined shape.
Non-explained reference number 180 is an insulation plate for insulating the substrate.
The related art is disclosed in Korean Patent No. 2002-59927 applied by the present applicant.
The operation of the switched reluctance motor having such a structure will now be described.
First, when power is supplied to a motor, a current flows through the winding coil 140 of the stator, and then reluctance torque is generated between the stator 100 and the rotor 200, thereby rotating the rotor 200. By the rotation of the rotor 200, the rotary shaft 300 coupled to the rotor 200 and the phase indication magnet 230 coupled to the rotary shaft 300 are rotated together.
And as the phase indication magnet 2300 is rotated, the hall sensor senses a phase of the phase indication magnet 230 and controls a current supplied to the winding coil 140 based on the sensed phase, thereby varying a speed of the rotor 200.
And, in case of stopping the rotor 200, the rotor 200 is stopped at an effective torque generation area by the phase indication magnet 230 connected to the rotor 200 and the parking magnet 160. For an initial activation or a reactivation, the rotor 200 is positioned at the effective torque generation area, a relative position with the stator 100.
Meanwhile, to reduce a manufacturing cost and improve productivity when the switched reluctance motor is mounted to household appliances such as a cleaner or the like, simplification of motor structure and reduction of manufacturing cost are essential and important issues to be achieved. Especially, in case that the motor is applied to a cleaner, protecting a motor from fine dust sucked to the cleaner is an important issue to be achieved.
However, the conventional switched reluctance motor has following problems.
The parking magnet 160 for positioning the rotor 200 at an effective torque generation area as a pair with the phase indication magnet 230 coupled to the rotary shaft 300, the hall sensor 150 for sensing a phase of the phase indication magnet 230, and the sensor substrate 170 connected to the hall sensor 150 are mounted at the holder 400. And the holder 400 is mounted at the stator 100. Therefore, the number of assembling processes for assembling each component becomes great, and the structure becomes complicated. Thus, assembling productivity is deteriorated, and it is not proper to be mass-produced. Particularly, when the holder 400 is coupled to the stator 100, such coupling should be made, precisely maintaining an assembly tolerance, which makes processing and assembling difficult.
In addition, because the winding coils 140 are exposed to the outside, when it is applied to a cleaner or the like, fine particles which are not filtered by a filter of the cleaner collide with and are accumulated on the winding coil 140. By the collision and the oxidization of the fine particles, insulation coating of the winding coil 140 is damaged, thereby shortening a life span of a component.